Stiles shook his head because he didn't want Allison with the other werewolves of the pack but he also didn't want her as Derek's slave. Derek was his and now he wasn't.
"It isn't the same, Derek," Stiles said softly because he had picked Derek because he liked Derek. He had wanted to stay with Derek. Allison barely knew Derek. "But it doesn't matter what I say. Nothing will change." He has lost his place. He has lost Derek. God, he just wanted to disappear. Maybe he should. He doubted anyone would notice.